willows: their growth, use, and importance. 7 
and California to New Mexico. It is a tree from 30 to 60 feet in 
height with dark brown rough bark. The twigs are long but not 
slender, reddish, or reddish-yellow in color. The leaves are dark 
green on both sides but somewhat paler beneath, from 3 to 8 inches 
long and from three-fifths of an inch to 1J inches wide. 
SOIL, MOISTURE, AND LIGHT. 
Willows grow best in deep, rich, moist, alluvial bottom lands. 
The tree willows will grow on very poor soils, but usually as stunted 
trees or only large shrubs. In very sandy soils where rainfall is 
plentiful they grow thriftily but rather slowly. In dry soils or in 
soils subject to drought during a portion of the season the willows 
survive but grow slowly and become stag-headed at an early age. 
On heavy clay soils they grow moderately well if there is sufficient 
moisture, otherwise they survive with difficulty and seldom become 
trees. In good soils the willows endure a wide range of moisture 
conditions. Their adaptability, or rather their ability to survive, 
and their methods of reproduction have been responsible for their 
being crowded into wet places. Because they are seen so often in 
such places, the willows are often considered moisture-loving or 
swamp trees. The truth of the matter is that willows live in such 
places in spite of the excessive moisture conditions rather than be- 
cause of them. Willows do, however, endure a period of inundation 
with less serious results than any but the southern swamp trees, 
such as cypress and water oak. They attain their best development 
along the lower Mississippi River, where these conditions and long 
growing seasons are found. 
All willows are intolerant of shade. For this reason mature 
stands of willow are usually very open and a second-story forest 
exists. The black willow is slightly more tolerant than the sand- 
bar willow and somewhat less than the peachleaf willow. Black 
willow is also slightly less tolerant than the cottonwood, although 
both are ranked as intolerant species. 
SUSCEPTIBILITY TO INJURY. 
INSECTS. 
Willows are subject to the attack of a large number of insects, 
but only in exceptional seasons is the damage of a serious nature. 
Injury by insects is of three kinds : Defoliation, twig or shoot cutting, 
and bark or wood boring. The most important of these insects are 
fully discussed and illustrated as to appearance, habits, character 
of work, and remedies by Dr. F. H. Chittenden, in Bureau of Forestry 
Bulletin, No. 46, on pages 63-80, which may be purchased from the 
Superintendent of Documents, Government Printing Office. It is 
